This invention relates to tube expanders, and more particularly, to hydraulic tube expanders.
In steam generators and other heat exchangers, expansion of a tube into full engagement with the entire depth of a tube sheet is a difficult task.
Mechanically rolling the tubes the full depth of the tube sheet is time consuming and results in high residual tensile stresses adjacent the transition region and necessitates the utilization of lubricants that require extensive post-cleaning operations in order to remove all residues thereof.
Explosive expansion is noisy, requires close controls and intensive specialized training of personnel and is highly regulated by governmental agencies.
Hydraulic expansion may be easily controlled, performed quickly with a minimum amount of personnel training, and when performed with demineralized water, the necessity for subsequent cleaning operations is practically eliminated; however, providing a satisfactory long-lasting seal adjacent the leading end is difficult as the leading end seal slides along the whole length of the tube within the tube sheet and is easily damaged in the process.